Renesas 70V261S55PF8

Overview

70V261S55PF8 from IDT is a high-speed 3.3V 16K × 16 true dual-port static RAM with independent left/right ports, 55 ns max access time, integrated semaphore and interrupt logic, and push-pull BUSY/INT outputs - used in real-time inter-processor communication systems requiring concurrent memory access without arbitration overhead.

For engineers reviewing the 70V261S55PF8 datasheet, 70V261S55PF8 pinout, 70V261S55PF8 application, or 70V261S55PF8 equivalent, this device supports simultaneous read/write to same address via hardware port arbitration, provides eight software-controllable binary semaphores, and delivers deterministic timing for deterministic multi-processor synchronization in telecom line cards and industrial motion controllers.

Technical Context

The 70V261S55PF8 implements fully asynchronous dual-port operation with separate CE/R/W/OE/UB/LB controls per port, enabling independent memory access without clock dependency. Its on-chip arbitration logic resolves contention using address and chip-enable matching, with BUSY assertion based solely on signal timing-not data direction.

It integrates two distinct functional blocks: a 256K-bit (16K × 16) SRAM array and an 8-location semaphore register space addressed by A0–A2. Semaphore access requires CE = VIH and SEM = VIL, while RAM access requires CE = VIL and SEM = VIH-ensuring strict mode separation and preventing accidental flag corruption during memory operations.

Key Specifications

Pinout & Package

70V261S55PF8 is housed in a 100-pin Thin Quad Flatpack (TQFP) measuring 14 mm × 14 mm × 1.4 mm, with exposed pad not electrically connected. Pin numbering follows standard counter-clockwise layout starting from top-left corner (Pin 1).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-port SRAM applications.

Compared with CY7C136-55JC and AS7C316000B-55PCN, the 70V261S55PF8 uniquely integrates hardware semaphore, interrupt, and configurable BUSY arbitration - reducing system-level complexity, eliminating external glue logic, and guaranteeing deterministic timing for safety-critical multi-processor coordination.

Availability

70V261S55PF8 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial motion control, medical imaging, and avionics applications requiring stable component supply, long-term lifecycle support, and guaranteed commercial-grade performance.

Supply support for 70V261S55PF8 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

IDT (Integrated Device Technology) is a fabless semiconductor company specializing in high-performance timing, memory, and interface solutions for communications, computing, and industrial markets.

The 70V261S55PF8 belongs to IDT's high-speed dual-port SRAM product line, designed specifically for deterministic inter-processor communication in real-time embedded systems where concurrent memory access and hardware-enforced synchronization are essential.

FAQ

What is the maximum access time specification for the 70V261S55PF8?

The 70V261S55PF8 has a maximum access time of 55 ns under commercial operating conditions (0°C to +70°C, VCC = 3.3 V ±0.3 V). This value applies to tAA, tACE, and tABE parameters and is guaranteed across the full voltage and temperature range specified in the datasheet.

How does the M/S pin affect BUSY pin functionality on the 70V261S55PF8?

When M/S = VIH, the 70V261S55PF8 operates as a master: BUSYL and BUSYR are push-pull outputs that indicate port contention. When M/S = VIL, it operates as a slave: BUSYL and BUSYR become inputs that internally inhibit writes when driven low - enabling cascaded width expansion with one master and multiple slaves.

Can the 70V261S55PF8 be used without enabling the semaphore or interrupt features?

Yes. The 70V261S55PF8 functions as a standard dual-port SRAM even when semaphore (SEM = VIH) and interrupt (addresses 3FFE/3FFF unused) features are disabled. Address locations 3FFE and 3FFF remain fully accessible as regular memory unless explicitly used as mailboxes - no configuration overhead is required for basic operation.

What is the power consumption of the 70V261S55PF8 in full standby mode?

In full standby mode (ISB3), where both ports are disabled with CMOS-level inputs (CE > VCC − 0.2 V, SEM > VCC − 0.2 V), the 70V261S55PF8 draws 1.0 mA typical current. This low-power state is achieved without external circuitry and maintains fast wake-up capability for real-time responsiveness.

How many semaphore flags does the 70V261S55PF8 provide, and how are they accessed?

The 70V261S55PF8 provides eight binary semaphore flags, addressed by A0–A2. They are accessed by setting SEM = VIL and CE = VIH - a condition that disables RAM access and routes I/O0–I/O15 to the semaphore register space. Writes occur on I/O0; reads return the flag value across all 16 I/O lines.